METHODS OF STORING SEED. 



557 



and may be swept into heaps ; they may then be placed in sacks, 

 and in the case of birch-catkins, shaken and pressed until the 

 catkins are broken up. Great care must be taken with birch 

 seed from the first, for it easily turns mouldy ; it should be 

 spread out in thin layers and frequently turned. Elm-seed 

 is also very liable to become mouldy ; in order to avoid the 

 trouble of storage, it is frequently sown in June as soon as it 

 is ripe. Berries of the mountain-ash are completely dried and 

 sown with their shrivelled skin ; or they may be macerated in 

 water, and the skin washed off the seed. Alder-catkins collected 

 in November and December are placed in moderately hot rooms 

 in order to open the catkins and allow the seed to fall ; the seed 

 is then separated from the catkin-scales by sifting. 



According to Burckhardt* the weights of air-dried seed of the 

 different broad-leaved species of trees are as follows : 



Acorns 



Hornbeam (without wings) 



Beech-nuts 



Alder (clean seed) 



Ash 



Sycamore (winged) 



Birch (according to number of scales) 

 Elm 



The method of treating cones in order to extract and clean 

 coniferous seeds will be described in the 5th chapter of Part III. 

 of this book. 



Section II. — Storing the Seeds of Forest Trees, 



1. General Account. 



Sylviculture shows that it is often advantageous to delay 

 sowing seed until the spring of the year after it has ripened. 

 Seed must therefore be stored for this purpose, and if this can 

 be done without seriously impairing its germinative power, the 



Siit'u uud Priaiizen. 



